Merge branch 'nlohmann:develop' into develop

.clang-tidy

@@ -17,6 +17,7 @@ Checks: '*,
          -cppcoreguidelines-pro-bounds-pointer-arithmetic,
          -cppcoreguidelines-pro-type-reinterpret-cast,
          -cppcoreguidelines-pro-type-union-access,
+         -cppcoreguidelines-rvalue-reference-param-not-moved,
          -cppcoreguidelines-virtual-class-destructor,
          -fuchsia-default-arguments-calls,
          -fuchsia-default-arguments-declarations,
@@ -35,10 +36,13 @@ Checks: '*,
          -llvm-header-guard,
          -llvm-include-order,
          -llvmlibc-*,
+         -misc-use-anonymous-namespace,
          -misc-confusable-identifiers,
+         -misc-include-cleaner,
          -misc-no-recursion,
          -misc-non-private-member-variables-in-classes,
          -modernize-concat-nested-namespaces,
+         -modernize-type-traits,
          -modernize-use-nodiscard,
          -modernize-use-trailing-return-type,
          -readability-function-cognitive-complexity,

.github/CONTRIBUTING.md

@@ -32,7 +32,7 @@ To make changes, you need to edit the following files:
 
 1. [`include/nlohmann/*`](https://github.com/nlohmann/json/tree/develop/include/nlohmann) - These files are the sources of the library. Before testing or creating a pull request, execute `make amalgamate` to regenerate `single_include/nlohmann/json.hpp` and `single_include/nlohmann/json_fwd.hpp`.
 
-2. [`tests/src/unit-*.cpp`](https://github.com/nlohmann/json/tree/develop/tests/src) - These files contain the [doctest](https://github.com/onqtam/doctest) unit tests which currently cover [100 %](https://coveralls.io/github/nlohmann/json) of the library's code.
+2. [`tests/src/unit-*.cpp`](https://github.com/nlohmann/json/tree/develop/tests/src) - These files contain the [doctest](https://github.com/onqtam/doctest) unit tests which currently cover [100 %](https://coveralls.io/github/nlohmann/json) of the library's code.  Before creating a pull request, execute `make pretty` to make sure that the style is correct, as this will be checked by the CI. 
 
    If you add or change a feature, please also add a unit test to this file. The unit tests can be compiled and executed with
 

.github/workflows/macos.yml

@@ -55,7 +55,7 @@ jobs:
     runs-on: macos-latest
     strategy:
       matrix:
-        standard: [11, 14, 17, 20]
+        standard: [11, 14, 17, 20, 23]
 
     steps:
       - uses: actions/checkout@v3

.github/workflows/ubuntu.yml

@@ -173,19 +173,35 @@ jobs:
       - name: Build
         run: cmake --build build --target ci_test_compiler_${{ matrix.compiler }}
 
-  ci_test_standards:
+  ci_test_standards_gcc:
     runs-on: ubuntu-latest
     container: ghcr.io/nlohmann/json-ci:v2.4.0
     strategy:
       matrix:
-        standard: [11, 14, 17, 20]
-        compiler: [gcc, clang]
+        standard: [11, 14, 17, 20, 23]
     steps:
       - uses: actions/checkout@v3
       - name: Run CMake
         run: cmake -S . -B build -DJSON_CI=On
       - name: Build
-        run: cmake --build build --target ci_test_${{ matrix.compiler }}_cxx${{ matrix.standard }}
+        run: cmake --build build --target ci_test_gcc_cxx${{ matrix.standard }}
+
+  ci_test_standards_clang:
+    runs-on: ubuntu-latest
+    container: silkeh/clang:latest
+    strategy:
+      matrix:
+        standard: [11, 14, 17, 20, 23]
+    steps:
+      - name: Install git and unzip
+        run: apt-get update ; apt-get install -y git unzip
+      - uses: actions/checkout@v3
+      - name: Get latest CMake and ninja
+        uses: lukka/get-cmake@latest
+      - name: Run CMake
+        run: cmake -S . -B build -DJSON_CI=On
+      - name: Build
+        run: cmake --build build --target ci_test_clang_cxx${{ matrix.standard }}
 
   ci_cuda_example:
     runs-on: ubuntu-latest

README.md

@@ -13,6 +13,7 @@
 [![Documentation](https://img.shields.io/badge/docs-mkdocs-blue.svg)](https://json.nlohmann.me)
 [![GitHub license](https://img.shields.io/badge/license-MIT-blue.svg)](https://raw.githubusercontent.com/nlohmann/json/master/LICENSE.MIT)
 [![GitHub Releases](https://img.shields.io/github/release/nlohmann/json.svg)](https://github.com/nlohmann/json/releases)
+[![Vcpkg Version](https://img.shields.io/vcpkg/v/nlohmann-json)](https://vcpkg.link/ports/nlohmann-json)
 [![Packaging status](https://repology.org/badge/tiny-repos/nlohmann-json.svg)](https://repology.org/project/nlohmann-json/versions)
 [![GitHub Downloads](https://img.shields.io/github/downloads/nlohmann/json/total)](https://github.com/nlohmann/json/releases)
 [![GitHub Issues](https://img.shields.io/github/issues/nlohmann/json.svg)](https://github.com/nlohmann/json/issues)
@@ -85,6 +86,7 @@ You can sponsor this library at [GitHub Sponsors](https://github.com/sponsors/nl
 - [Steve Sperandeo](https://github.com/homer6)
 - [Robert Jefe Lindstädt](https://github.com/eljefedelrodeodeljefe)
 - [Steve Wagner](https://github.com/ciroque)
+- [Lion Yang](https://github.com/LionNatsu)
 
 Thanks everyone!
 
@@ -300,7 +302,7 @@ Note the difference between serialization and assignment:
 json j_string = "this is a string";
 
 // retrieve the string value
-auto cpp_string = j_string.get<std::string>();
+auto cpp_string = j_string.template get<std::string>();
 // retrieve the string value (alternative when a variable already exists)
 std::string cpp_string2;
 j_string.get_to(cpp_string2);
@@ -309,7 +311,7 @@ j_string.get_to(cpp_string2);
 std::string serialized_string = j_string.dump();
 
 // output of original string
-std::cout << cpp_string << " == " << cpp_string2 << " == " << j_string.get<std::string>() << '\n';
+std::cout << cpp_string << " == " << cpp_string2 << " == " << j_string.template get<std::string>() << '\n';
 // output of serialized value
 std::cout << j_string << " == " << serialized_string << std::endl;
 ```
@@ -482,7 +484,7 @@ for (auto& element : j) {
 }
 
 // getter/setter
-const auto tmp = j[0].get<std::string>();
+const auto tmp = j[0].template get<std::string>();
 j[1] = 42;
 bool foo = j.at(2);
 
@@ -690,7 +692,7 @@ You can switch off implicit conversions by defining `JSON_USE_IMPLICIT_CONVERSIO
 // strings
 std::string s1 = "Hello, world!";
 json js = s1;
-auto s2 = js.get<std::string>();
+auto s2 = js.template get<std::string>();
 // NOT RECOMMENDED
 std::string s3 = js;
 std::string s4;
@@ -699,7 +701,7 @@ s4 = js;
 // Booleans
 bool b1 = true;
 json jb = b1;
-auto b2 = jb.get<bool>();
+auto b2 = jb.template get<bool>();
 // NOT RECOMMENDED
 bool b3 = jb;
 bool b4;
@@ -708,7 +710,7 @@ b4 = jb;
 // numbers
 int i = 42;
 json jn = i;
-auto f = jn.get<double>();
+auto f = jn.template get<double>();
 // NOT RECOMMENDED
 double f2 = jb;
 double f3;
@@ -751,9 +753,9 @@ j["age"] = p.age;
 
 // convert from JSON: copy each value from the JSON object
 ns::person p {
-    j["name"].get<std::string>(),
-    j["address"].get<std::string>(),
-    j["age"].get<int>()
+    j["name"].template get<std::string>(),
+    j["address"].template get<std::string>(),
+    j["age"].template get<int>()
 };
 ```
 
@@ -770,7 +772,7 @@ std::cout << j << std::endl;
 // {"address":"744 Evergreen Terrace","age":60,"name":"Ned Flanders"}
 
 // conversion: json -> person
-auto p2 = j.get<ns::person>();
+auto p2 = j.template get<ns::person>();
 
 // that's it
 assert(p == p2);
@@ -797,13 +799,13 @@ namespace ns {
 ```
 
 That's all! When calling the `json` constructor with your type, your custom `to_json` method will be automatically called.
-Likewise, when calling `get<your_type>()` or `get_to(your_type&)`, the `from_json` method will be called.
+Likewise, when calling `template get<your_type>()` or `get_to(your_type&)`, the `from_json` method will be called.
 
 Some important things:
 
 * Those methods **MUST** be in your type's namespace (which can be the global namespace), or the library will not be able to locate them (in this example, they are in namespace `ns`, where `person` is defined).
 * Those methods **MUST** be available (e.g., proper headers must be included) everywhere you use these conversions. Look at [issue 1108](https://github.com/nlohmann/json/issues/1108) for errors that may occur otherwise.
-* When using `get<your_type>()`, `your_type` **MUST** be [DefaultConstructible](https://en.cppreference.com/w/cpp/named_req/DefaultConstructible). (There is a way to bypass this requirement described later.)
+* When using `template get<your_type>()`, `your_type` **MUST** be [DefaultConstructible](https://en.cppreference.com/w/cpp/named_req/DefaultConstructible). (There is a way to bypass this requirement described later.)
 * In function `from_json`, use function [`at()`](https://json.nlohmann.me/api/basic_json/at/) to access the object values rather than `operator[]`. In case a key does not exist, `at` throws an exception that you can handle, whereas `operator[]` exhibits undefined behavior.
 * You do not need to add serializers or deserializers for STL types like `std::vector`: the library already implements these.
 
@@ -888,8 +890,8 @@ namespace nlohmann {
             if (j.is_null()) {
                 opt = boost::none;
             } else {
-                opt = j.get<T>(); // same as above, but with
-                                  // adl_serializer<T>::from_json
+                opt = j.template get<T>(); // same as above, but with
+                                           // adl_serializer<T>::from_json
             }
         }
     };
@@ -916,7 +918,7 @@ namespace nlohmann {
         // note: the return type is no longer 'void', and the method only takes
         // one argument
         static move_only_type from_json(const json& j) {
-            return {j.get<int>()};
+            return {j.template get<int>()};
         }
 
         // Here's the catch! You must provide a to_json method! Otherwise, you
@@ -1020,19 +1022,19 @@ assert(j == "stopped");
 
 // json string to enum
 json j3 = "running";
-assert(j3.get<TaskState>() == TS_RUNNING);
+assert(j3.template get<TaskState>() == TS_RUNNING);
 
 // undefined json value to enum (where the first map entry above is the default)
 json jPi = 3.14;
-assert(jPi.get<TaskState>() == TS_INVALID );
+assert(jPi.template get<TaskState>() == TS_INVALID );
 ```
 
 Just as in [Arbitrary Type Conversions](#arbitrary-types-conversions) above,
 - `NLOHMANN_JSON_SERIALIZE_ENUM()` MUST be declared in your enum type's namespace (which can be the global namespace), or the library will not be able to locate it, and it will default to integer serialization.
 - It MUST be available (e.g., proper headers must be included) everywhere you use the conversions.
 
 Other Important points:
-- When using `get<ENUM_TYPE>()`, undefined JSON values will default to the first pair specified in your map. Select this default pair carefully.
+- When using `template get<ENUM_TYPE>()`, undefined JSON values will default to the first pair specified in your map. Select this default pair carefully.
 - If an enum or JSON value is specified more than once in your map, the first matching occurrence from the top of the map will be returned when converting to or from JSON.
 
 ### Binary formats (BSON, CBOR, MessagePack, UBJSON, and BJData)

cmake/ci.cmake

@@ -13,12 +13,12 @@ execute_process(COMMAND ${ASTYLE_TOOL} --version OUTPUT_VARIABLE ASTYLE_TOOL_VER
 string(REGEX MATCH "[0-9]+(\\.[0-9]+)+" ASTYLE_TOOL_VERSION "${ASTYLE_TOOL_VERSION}")
 message(STATUS "🔖 Artistic Style ${ASTYLE_TOOL_VERSION} (${ASTYLE_TOOL})")
 
-find_program(CLANG_TOOL NAMES clang++-HEAD clang++-16 clang++-15 clang++-14 clang++-13 clang++-12 clang++-11 clang++)
+find_program(CLANG_TOOL NAMES clang++-HEAD clang++ clang++-17 clang++-16 clang++-15 clang++-14 clang++-13 clang++-12 clang++-11 clang++)
 execute_process(COMMAND ${CLANG_TOOL} --version OUTPUT_VARIABLE CLANG_TOOL_VERSION ERROR_VARIABLE CLANG_TOOL_VERSION)
 string(REGEX MATCH "[0-9]+(\\.[0-9]+)+" CLANG_TOOL_VERSION "${CLANG_TOOL_VERSION}")
 message(STATUS "🔖 Clang ${CLANG_TOOL_VERSION} (${CLANG_TOOL})")
 
-find_program(CLANG_TIDY_TOOL NAMES clang-tidy-15 clang-tidy-14 clang-tidy-13 clang-tidy-12 clang-tidy-11 clang-tidy)
+find_program(CLANG_TIDY_TOOL NAMES clang-tidy-17 clang-tidy-16 clang-tidy-15 clang-tidy-14 clang-tidy-13 clang-tidy-12 clang-tidy-11 clang-tidy)
 execute_process(COMMAND ${CLANG_TIDY_TOOL} --version OUTPUT_VARIABLE CLANG_TIDY_TOOL_VERSION ERROR_VARIABLE CLANG_TIDY_TOOL_VERSION)
 string(REGEX MATCH "[0-9]+(\\.[0-9]+)+" CLANG_TIDY_TOOL_VERSION "${CLANG_TIDY_TOOL_VERSION}")
 message(STATUS "🔖 Clang-Tidy ${CLANG_TIDY_TOOL_VERSION} (${CLANG_TIDY_TOOL})")
@@ -30,7 +30,7 @@ execute_process(COMMAND ${CPPCHECK_TOOL} --version OUTPUT_VARIABLE CPPCHECK_TOOL
 string(REGEX MATCH "[0-9]+(\\.[0-9]+)+" CPPCHECK_TOOL_VERSION "${CPPCHECK_TOOL_VERSION}")
 message(STATUS "🔖 Cppcheck ${CPPCHECK_TOOL_VERSION} (${CPPCHECK_TOOL})")
 
-find_program(GCC_TOOL NAMES g++-latest g++-HEAD g++-12 g++-11 g++-10)
+find_program(GCC_TOOL NAMES g++-latest g++-HEAD g++-13 g++-12 g++-11 g++-10)
 execute_process(COMMAND ${GCC_TOOL} --version OUTPUT_VARIABLE GCC_TOOL_VERSION ERROR_VARIABLE GCC_TOOL_VERSION)
 string(REGEX MATCH "[0-9]+(\\.[0-9]+)+" GCC_TOOL_VERSION "${GCC_TOOL_VERSION}")
 message(STATUS "🔖 GCC ${GCC_TOOL_VERSION} (${GCC_TOOL})")
@@ -95,6 +95,7 @@ file(GLOB_RECURSE SRC_FILES ${PROJECT_SOURCE_DIR}/include/nlohmann/*.hpp)
 # -Wno-extra-semi-stmt            The library uses std::assert which triggers this warning.
 # -Wno-padded                     We do not care about padding warnings.
 # -Wno-covered-switch-default     All switches list all cases and a default case.
+# -Wno-unsafe-buffer-usage        Otherwise Doctest would not compile.
 # -Wno-weak-vtables               The library is header-only.
 # -Wreserved-identifier           See https://github.com/onqtam/doctest/issues/536.
 
@@ -107,6 +108,7 @@ set(CLANG_CXXFLAGS
     -Wno-extra-semi-stmt
     -Wno-padded
     -Wno-covered-switch-default
+    -Wno-unsafe-buffer-usage
     -Wno-weak-vtables
     -Wno-reserved-identifier
 )
@@ -437,7 +439,7 @@ add_custom_target(ci_test_clang
 # Different C++ Standards.
 ###############################################################################
 
-foreach(CXX_STANDARD 11 14 17 20)
+foreach(CXX_STANDARD 11 14 17 20 23)
     add_custom_target(ci_test_gcc_cxx${CXX_STANDARD}
         COMMAND CXX=${GCC_TOOL} CXXFLAGS="${GCC_CXXFLAGS}" ${CMAKE_COMMAND}
             -DCMAKE_BUILD_TYPE=Debug -GNinja
@@ -898,7 +900,7 @@ add_custom_target(ci_cmake_flags
 # Use more installed compilers.
 ###############################################################################
 
-foreach(COMPILER g++-4.8 g++-4.9 g++-5 g++-6 g++-7 g++-8 g++-9 g++-10 g++-11 clang++-3.5 clang++-3.6 clang++-3.7 clang++-3.8 clang++-3.9 clang++-4.0 clang++-5.0 clang++-6.0 clang++-7 clang++-8 clang++-9 clang++-10 clang++-11 clang++-12 clang++-13 clang++-14)
+foreach(COMPILER g++-4.8 g++-4.9 g++-5 g++-6 g++-7 g++-8 g++-9 g++-10 g++-11 clang++-3.5 clang++-3.6 clang++-3.7 clang++-3.8 clang++-3.9 clang++-4.0 clang++-5.0 clang++-6.0 clang++-7 clang++-8 clang++-9 clang++-10 clang++-11 clang++-12 clang++-13 clang++-14 clang++-15 clang++-16 clang++-17)
     find_program(COMPILER_TOOL NAMES ${COMPILER})
     if (COMPILER_TOOL)
         unset(ADDITIONAL_FLAGS)

docs/examples/from_json__default_constructible.cpp

@@ -31,7 +31,7 @@ int main()
     j["address"] = "744 Evergreen Terrace";
     j["age"] = 60;
 
-    auto p = j.get<ns::person>();
+    auto p = j.template get<ns::person>();
 
     std::cout << p.name << " (" << p.age << ") lives in " << p.address << std::endl;
 }

docs/examples/from_json__non_default_constructible.cpp

@@ -47,7 +47,7 @@ int main()
     j["address"] = "744 Evergreen Terrace";
     j["age"] = 60;
 
-    auto p = j.get<ns::person>();
+    auto p = j.template get<ns::person>();
 
     std::cout << p.name << " (" << p.age << ") lives in " << p.address << std::endl;
 }

docs/examples/get__PointerType.cpp

@@ -9,11 +9,11 @@ int main()
     json value = 17;
 
     // explicitly getting pointers
-    auto p1 = value.get<const json::number_integer_t*>();
-    auto p2 = value.get<json::number_integer_t*>();
-    auto p3 = value.get<json::number_integer_t* const>();
-    auto p4 = value.get<const json::number_integer_t* const>();
-    auto p5 = value.get<json::number_float_t*>();
+    auto p1 = value.template get<const json::number_integer_t*>();
+    auto p2 = value.template get<json::number_integer_t*>();
+    auto p3 = value.template get<json::number_integer_t* const>();
+    auto p4 = value.template get<const json::number_integer_t* const>();
+    auto p5 = value.template get<json::number_float_t*>();
 
     // print the pointees
     std::cout << *p1 << ' ' << *p2 << ' ' << *p3 << ' ' << *p4 << '\n';

docs/examples/get__ValueType_const.cpp

@@ -22,14 +22,14 @@ int main()
     };
 
     // use explicit conversions
-    auto v1 = json_types["boolean"].get<bool>();
-    auto v2 = json_types["number"]["integer"].get<int>();
-    auto v3 = json_types["number"]["integer"].get<short>();
-    auto v4 = json_types["number"]["floating-point"].get<float>();
-    auto v5 = json_types["number"]["floating-point"].get<int>();
-    auto v6 = json_types["string"].get<std::string>();
-    auto v7 = json_types["array"].get<std::vector<short>>();
-    auto v8 = json_types.get<std::unordered_map<std::string, json>>();
+    auto v1 = json_types["boolean"].template get<bool>();
+    auto v2 = json_types["number"]["integer"].template get<int>();
+    auto v3 = json_types["number"]["integer"].template get<short>();
+    auto v4 = json_types["number"]["floating-point"].template get<float>();
+    auto v5 = json_types["number"]["floating-point"].template get<int>();
+    auto v6 = json_types["string"].template get<std::string>();
+    auto v7 = json_types["array"].template get<std::vector<short>>();
+    auto v8 = json_types.template get<std::unordered_map<std::string, json>>();
 
     // print the conversion results
     std::cout << v1 << '\n';

docs/examples/nlohmann_define_type_intrusive_explicit.cpp

@@ -45,13 +45,13 @@ int main()
 
     // deserialization: json -> person
     json j2 = R"({"address": "742 Evergreen Terrace", "age": 40, "name": "Homer Simpson"})"_json;
-    auto p2 = j2.get<ns::person>();
+    auto p2 = j2.template get<ns::person>();
 
     // incomplete deserialization:
     json j3 = R"({"address": "742 Evergreen Terrace", "name": "Maggie Simpson"})"_json;
     try
     {
-        auto p3 = j3.get<ns::person>();
+        auto p3 = j3.template get<ns::person>();
     }
     catch (json::exception& e)
     {

docs/examples/nlohmann_define_type_intrusive_macro.cpp

@@ -33,13 +33,13 @@ int main()
 
     // deserialization: json -> person
     json j2 = R"({"address": "742 Evergreen Terrace", "age": 40, "name": "Homer Simpson"})"_json;
-    auto p2 = j2.get<ns::person>();
+    auto p2 = j2.template get<ns::person>();
 
     // incomplete deserialization:
     json j3 = R"({"address": "742 Evergreen Terrace", "name": "Maggie Simpson"})"_json;
     try
     {
-        auto p3 = j3.get<ns::person>();
+        auto p3 = j3.template get<ns::person>();
     }
     catch (json::exception& e)
     {

docs/examples/nlohmann_define_type_intrusive_with_default_explicit.cpp

@@ -46,10 +46,10 @@ int main()
 
     // deserialization: json -> person
     json j2 = R"({"address": "742 Evergreen Terrace", "age": 40, "name": "Homer Simpson"})"_json;
-    auto p2 = j2.get<ns::person>();
+    auto p2 = j2.template get<ns::person>();
 
     // incomplete deserialization:
     json j3 = R"({"address": "742 Evergreen Terrace", "name": "Maggie Simpson"})"_json;
-    auto p3 = j3.get<ns::person>();
+    auto p3 = j3.template get<ns::person>();
     std::cout << "roundtrip: " << json(p3) << std::endl;
 }